On Friday, 8th September we were delighted to invite Dan Ahern from the Wiltshire Bat group along to the hall to lead us on an evening ‘batwalk’ through the village. In Wiltshire we are lucky to have 11 of the 18 species of UK bats living in the county, and on a fine summer’s evening we were hopeful to encounter at least a few of these on our walk.
Dan had brought along several handheld bat detectors so that we could hopefully ‘hear’ as well as see the bats. The detectors work by converting the ultrasonic calls of the bats into a series of clicks, each species of bat giving a slightly different frequency of click ranging from 22Hz for a noctule bat through to 57Hz for a soprano pipistrelle.
Among the other interesting facts about bats Dan told us were that when ready to give birth the females often group together in summer roosts, which can number several hundred bats. The young usually become independent at about 6 to 8 weeks, but before that they cling to mum’s abdomen whilst she flits around searching for food, predominantly flying insects. Did you know that not all bats hang upside down when roosting, many species simply hide in crevices in old buildings which is why churches are often a good place to see bats as they emerge at dusk.
So after a short introductory talk we headed off to the road bridge over the Kennet in the village, but apart from spotting a roosting white egret and a signal crayfish in the river we did not detect any bats. Undeterred we headed for the churchyard where we did at least detect and see some pipistrelles.
But our main objective was ‘fairyland’ and the bridge over the river. We arrived there just before dark, and our detectors were soon clicking wildly as we started to pick up several different bat calls. Aided by our torches we saw several daubentons bats skimming the water surface and also picked up the a noctule bat, one of the largest British species with a ‘handwing’ span of up to 30cms.
It was a fascinating evening and thoroughly enjoyed by all. The Wiltshire Bat group is a voluntary organisation and we were very grateful to Dan to give up his time and also to thank the Bat Conservation Trust for their work in supporting these secretive and unique mammals.
Paul Outridge
Analysis of bats 'heard' through the bat monitors that evening:
Bat species No. of times located
Barbastelle 2
Common Pipistrelle 96
Myotis Species 29
Natterer’s 4
Noctule 4
Serotine 12
Soprano Pipistrelle 39
Whiskered 4
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